Embed Size (px)
Citation preview
1Friday, September 26th, 2014
Coupled Modelling of Membrane Desalination
Dana Suwwan, Isam Janajreh, Raed Hashaikeh
Waste to Energy lab, Mechanical and Materials Engineering Department,Masdar Institute of Science and Technology, Abu Dhabi, UAE
[email protected], [email protected], [email protected]
International Conference on Industrial Waste & Wastewater Treatment & Valorization (IWWATV 2015)
21-23rd May, 2015, Athens 15773, Greece
IWWATV2015
2
PRESENTATION OUTLINE
Conclusions
Results and discussions
Model development
Objectives and Scope of work
Overview of DCMD
Ref.: earth.rice.edu
“Abu Dhabi faces acute water scarcity.” [Online]. Available: http://gulfnews.com/news/uae/environment/abu-dhabi-faces-acute-water-scarcity-1.1398723.
[Accessed: 25-Mar-2015].
“UAE may run out of groundwater by 2030.” [Online]. Available: http://gulfnews.com/news/uae/environment/uae-may-run-out-of-groundwater-by-2030-
1.1475546#.VQ6Cr00c72U.facebook. [Accessed: 25-Mar-2015].
“$1 million award for water scarcity solutions,” Dubai Eye. [Online]. Available: http://dubaieye1038.com/1-million-award-for-water-scarcity-solutions/. [Accessed:
25-Mar-2015].
IWWATV2015
3
OVERVIEW: DCMD
Importance of MD• Based on World watch Institute, more than two-thirds of the world’s population will face potable water shortage in 2025 [1]
Applications of MD• Desalination [1]
• Pharmaceutical [2]
• Juice & Food Industry [2]
• Sports wear (jackets & shoes) [3]
Configuration of MD
• Multi-Stage Flash (MSF)
• Multi-Effect Distillation (MED)
• Vapor Compression (VC)
• Freezing, Humidification/Dehumidification
• Electro-Dialysis (ED)
• Reverse Osmosis (RO)
• Membrane Distillation (MD)
Direct Contact Membrane Distillation (DCMD
Air Gap Membrane Distillation (AGMD)
Vacuum Membrane Distillation (VMD)
Sweeping Gas Membrane Distillation (SGMD)
[1] L. F. Greenlee, D. F. Lawler, B. D. Freeman, B. Marrot, and P. Moulin, “Reverse osmosis desalination: Water sources, technology, and today’s challenges,” Water Res., vol. 43, no. 9,
pp. 2317–2348, May 2009.
[2] K. W. Lawson and D. R. Lloyd, “Membrane distillation. II. Direct contact MD,” J. Membr. Sci., vol. 120, no. 1, pp. 123–133, Oct. 1996.
[3] http://amphibiox.geox.com/amphibiox2014/en_gb/about/
IWWATV2015
4
LITERATURE REVIEW AND PROBLEM STATEMENT
Literature Survey: DCMD modelling
• Earlier semi-empirical model [5]
• CFD based models [1-2,4]
• Molecular Dynamics Simulation [6-7]
Different CFD models and previous work by authors
• Independent channel flow [6]
• Conjugated Heat transfer [7-8]
Problem statement
• Assess the current coupling strategy for the model flow as a conjugate heat problem
[1] L. F. Greenlee, D. F. Lawler, B. D. Freeman, B. Marrot, and P. Moulin, “Reverse osmosis desalination: Water sources, technology, and today’s challenges,” Water Res., vol. 43, no. 9, pp. 2317–2348, May 2009.
[2] K. W. Lawson and D. R. Lloyd, “Membrane distillation. II. Direct contact MD,” J. Membr. Sci., vol. 120, no. 1, pp. 123–133, Oct. 1996.
[4] M. Khayet, “Membranes and theoretical modeling of membrane distillation: A review,” Adv. Colloid Interface Sci., vol. 164, no. 1–2, pp. 56–88, May 2011.
[5] J. Phattaranawik, R. Jiraratananon, and A. G. Fane, “Heat transport and membrane distillation coefficients in direct contact membrane distillation,” J. Membr. Sci., vol. 212, no. 1–2, pp. 177–193, Feb. 2003.
[6]Janajreh, Isam; Suwwan Dana; Fath Hassan, “Flow analysis of low energy direct contact membrane desalination,” Int. J. Therm. Environ. Eng., vol. 8, no. 2, pp. 133–138, 2014
[7] M. Sohail, “Singularity free algorithm for molecular dynamics simulation of rigid polyatomics,” vol. 34, no. 2, pp. 327–331, 1977.
[8] S.-H. Ko, N. Kim, and S. Jha, “Numerical methodologies for investigation of moderate-velocity flow using a hybrid computational fluid dynamics – molecular dynamics simulation approach†,” J. Mech. Sci. Technol. 28 1 2014 245253,
vol. 28, no. 1, pp. 245–253, Jul. 2013.
[9] L.-Z. Zhang, C.-H. Liang, and L.-X. Pei, “Conjugate heat and mass transfer in membrane-formed channels in all entry regions,” Int. J. Heat Mass Transf., vol. 53, no. 5–6, pp. 815–824, Feb. 2010.
[10] I. Janajreh and D. Suwwan, “Numerical simulation of membrane desalination in a conjugated heat transfer configuration: Role of Spacers,” presented at the International Renewable and Sustainable Conference.
.
IWWATV2015
5
OBJECTIVES AND SCOPE OF THE WORK
IWWATV2015
Conclude the applicability of Coupling the flow to the DCMD mechanism
Analyze the influence reflected in the temperature profiles, temperature polarization and mass flux
Apply an Algorithmic model to identify the effect of coupling and decoupling of the flow on the yield of DCMD
The primary objectives entitles to investigate the applicability of decoupling the flow as a conjugate heat problem and its corresponding effects on the yields of the system which in this case are the Temperature polarization coefficient (TPC), mass flux and thermal efficiency
6
MODEL DEVELOPMENT: THEORETICAL AND COMPUTATIONAL MODELLING
Flow Conditions Value Unit
Channel length 14 mm
Channel Height 1 mm
Membrane Thickness 130 𝜇m
Feed Inlet Temperature 40 °C
Permeate Inlet Temperature 25 °C
Flow Reynolds Number 10 -
Counter flow Configuration
Model Assumptions
2D- Cartesian Coordinates (x &y)
Steady state, Incompressible & Non-Isothermal flow
Full developed flow for Velocity profile (Parabolic)
Feed and Permeate assumed to be of single species
No Slip Condition at Membrane & Channel Walls
IWWATV2015
Hydrophobic Membrane
T. Feed
T. Permeate
T. Feed Membrane
T. Permeate Membrane
Vapor Flow
Hot Feed Flow
Cold Permeate Flow
1 mm
1 mm
130 m
14 mm
Continuity: c
i
i Sx
u
t
Momentum: ii
j
ij
j
jii Sgxx
uu
t
u
Energy: h
j
jj
it
tp
i
i
i
SJhx
TcK
xpeu
x
])
Pr[()]([
7Friday, May 29, 2015
Mass Transfer Module
𝐽′′ = 𝑐𝑚 𝑃𝑓𝑠𝑎𝑡 − 𝑃𝑝
𝑠𝑎𝑡 [1]
𝑃𝑖 𝑝𝑢𝑟𝑒𝑠𝑎𝑡 𝑇 = exp 23.1964 −
3816.44
𝑇−46.13, 𝑖 ∈ 𝑓, 𝑝 [2]
cm = ck + cp = 1.064 α Tε r
τ δm
Mw
R Tmt+ 0.125 β T
ε r2
τ δm
Mw Pm
R Tmt ηv[3]
knudsen and Poiseuille
Heat Transfer Module
𝑄𝑚 = 𝑄𝑣 + 𝑄𝑐 [4]
𝑄𝑣 = 𝐽′′Δ𝐻 = 𝐽′′(𝐻𝑚,𝑓 − 𝐻𝑚,𝑝) [5]
𝐻𝑚,𝑖 = 1.7535 𝑇𝑚,𝑖 + 2024.3, 𝑖 ∈ 𝑓, 𝑝 [6]
𝑄𝑐 = −𝑘𝑚
𝛿𝑚𝑇𝑚,𝑓 − 𝑇𝑚,𝑝 [7]
𝑘𝑚 = 휀𝑘𝑔 + 1 − 휀 𝑘𝑏 [8]
MODEL DEVELOPMENT: EVALUATION OF FLUX AND FLOW METRICS
IWWATV2015
Tzahi Y. Cath, “Experimental study of desalination using DCMD: A new approach to flux enhancement”, J. Membrane Science, 228 (2004)5-16Tsung-Ching Chen, Chii-Dong Ho, Ho-Ming Yeh, “ Theoretical and experimental analysis of direct contact membrane desalination”, J. Membrane Sceince, 330(2009)279-287B. L. Pangarkar, S. K. Deshmukh, V. S. Sapkal, and R. S. Sapkal, “Review of membrane distillation process for water purification,” Desalination Water
Treat., vol. 0, no. 0, pp. 1–23, Nov. 2014.
M. Khayet, “Membranes and theoretical modeling of membrane distillation: A review,” Adv. Colloid Interface Sci., vol. 164, no. 1–2, pp. 56–88, May 2011.
K. W. Lawson and D. R. Lloyd, “Membrane distillation. II. Direct contact MD,” J. Membr. Sci., vol. 120, no. 1, pp. 123–133, Oct. 1996.
A. Alkhudhiri, N. Darwish, and N. Hilal, “Membrane distillation: A comprehensive review,” Desalination, vol. 287, pp. 2–18, Feb. 2012.
8
Temperature Polarization
It is known that the DCMDefficiency is limited by the heattransfer through the boundarylayers. In order to define andquantify the boundary layerresistance over the total heattransfer resistance, thetemperature polarization isused.
𝜃 =𝑇𝑚,𝑓−𝑇𝑚,𝑝
𝑇𝑏,𝑓−𝑇𝑏,𝑝[9]
Thermal Efficiency
This metric is governed by the fractionof the heat used as latent heat ofevaporation instead of the lostconduction fraction. This efficiency canbe written as
[10]
[11]
𝑄𝑚 = 𝐽". 𝛥𝐻𝑚 + 𝑘𝑚 𝑇𝑚𝑓 − 𝑇𝑚𝑝 𝛿𝑚
𝜂 = 𝐽". 𝛥 𝐻𝑚 𝑄𝑚
IWWATV2015
Other flow metrics:
Parameter Symbol (unit)
Value
Knudsen & Poiseuille fluid
model
α T , β T 1
Molar Weight Mw(kg/mol) 0.018
Membrane Thickness
δm (μm) 130
Gas Constant R(J/mol. K) 8.3143
Pores Radius r(nm) 50
Gas Viscosity ηv( Ns m2) 9.29e-6
Porosity ε 0.7
Membrane Thermal Conductivity
kp(W/mK) 0.178
MODEL DEVELOPMENT: EVALUATION OF FLUX AND FLOW METRICS CONT’D
9Friday, May 29, 2015
MODEL DEVELOPMENT: SOLUTION FLOW CHART/ALGORITHMS
IWWATV2015
10
RESULT I: VELOCITY AND TEMPERATURE CONTOUR
Friday, May 29, 2015
Vel. (ms-1)45.0
40.0
35.0
30.0
25.0
Temp. (Co)0.020
0.015
0.010
0.005
0.000
• The fluid flow as fully developed fluid• No intense temperature mixing within each channel• It demonstrates a good thermal insulation for the membrane
IWWATV2015
11
RESULTS II: TEMPERATURE PROFILES & TEMPERATURE POLARIZATION COEFFICIENT (TPC)
IWWATV2015
Comments:
- Red for decoupled flow, blue for coupled flow
- Temperature profiles comply with literature and are unchanged for the two flows
- TPC is depicted as slightly higher for the decoupled flow, however still less than 2%
12
RESULT III: MASS FLUX AND THERMAL EFFICIENCY EVALUATION
Friday, May 29, 2015
IWWATV2015
Mass flux and thermal efficiency evaluation by employing equations (slide-7-8)
- Mass flux for decoupled flow are slightly higher than a fully coupled flow- Thermal efficiency also depicted similar trends such as mass flux and TPC with the decoupled flow
resulting in a slightly higher efficiency due to the temperatures being a bit overestimated
13
CONCLUSIONS
Counter flow DCMD configuration was modelled using conjugate heat transfer with and without accounting to the latent heat of evaporation/condensation
Highlights
• Temperature distributions were insignificantly affected as the heat of diffusion counts less than 1% of the conduction heat
• Temperature polarization reported slightly lower for the coupled model• Mass flux incurred was found to be in phase with the temperature polarization trend and thus
reflecting slightly lower for the coupled model
Main Conclusions
• Coupling the flow altogether results in a very negligible difference on the output parameters• The sufficiency of the uncoupled model is presented and validated to be adequate enough for
this scope of work
Friday, May 29, 2015
IWWATV2015
14
Thank YouDana Suwwan is a Master’s students and a Research Assistant in her final year
in Waste to Energy Lab at Masdar Institute of Science and Technology. Her
interests lie within developing a full-fledged study on the possible ways to
enhance the productivity of the DCMD, be it energy wise or on a molecular
development level. Dana can be reached at [email protected]
Dr. Isam Janajreh received his PhD and Masters from Virginia Tech in
Engineering Science and Mechanics and Mechanical Engineering respectively. He
received his BS in Mechanical Engineering from Jordan University of Science and
Technology. Dr. Janajreh's focus was on solid-fluid interactions, turbulence
modeling and mixing, and thermo mechanical coupling. He was Visiting Professor
at Virginia Tech at the Engineering Science and Mechanics and Math's
departments through 1998 and later joined Michelin R&D, USA as a Tire and
Automotive Research Engineer, analyzing wet tire traction and nonlinear structure
analysis, vehicle dynamics, and rubber material modeling. Dr. Janajreh joined
Masdar in 2007 continuing his research while also teaching Advanced Renewable
Energy Conversion System, Fundamentals of Combustion, Advanced Fluid
Dynamics, and Computational Fluid Dynamics. He has authored over 15
referenced publications on fluid dynamics and structure interaction, made more
than 35 contributions to international conferences and is a key contributor to three
Michelin patents (Catamaran, Primacy, X-one)and three books (traction, rolling,
resistance noise). Dr. Janajreh can be reached at [email protected].
Lecturer’s biographies
IWWATV2015
